I have found there are a few sellers on eBay advertising "6497" movements.  Unfortunately, many times they are real good looking copies of the ETA movements, and are not even Swiss.

Some History....  Unitas developed a 17 jewel 18,000 bph watch movement a few decades ago.  This popular movement was used in several pocket watches in the 1970s and 1980s.  ETA acquired Unitas, and continued production of this movement, still being marked with the Unitas trademark.  More recently, ETA began marking the old Unitas design with the ETA trade mark.  This mark can be found next to the balance cock upon close inspection.

These days...  The genuine Swiss Unitas/ETA 6497 and 6498 are used in may modern wind up mechanical pocket watches, from such brands as Jean Marcel, Hamilton, Camero, etc.  With the popularity of oversized wrist watches, it is also used in many wind up wrist watches, the most famous being Panerai.

CAUTION!  Study the photos and read the ad carefully.  Many of these unscrupulous sellers use trademark names like "Incabloc", "Glucydur", and "Nivarox", which usually denote genuine Swiss movements.  However, even though these trademarks are touted in the description, it doesn't mean it is Swiss.

Other sellers mention "fits Panerai" etc.  However, it is a not a genuine Panerai movement. It is simply a knock off.

The Chinese have copied the true ETA movement, and are producing nearly identical movements with superior finishes, etc.  However, most if not all of the real ETA 6497 and 6498 movements are marked SWISS. 

If it is not marked SWISS, ask the seller!  Most (not all) sellers will fess up that the item in not Swiss when asked directly. 

If you are still not convinced, buy elsewhere!  Sometimes when the price is too good to be true, it probably is Chinese!